The proposed research program will elucidate the role of complement in the evolution of myocardial inflammation and infarct size in man and in the baboon. The mechanism for the antibody-independent activation of the complement system by heart subcellular organelles will be characterized with respect to its initiation and inhibition by various agents. Localization of various complement components within infarcted myocardium will be determined temporally at the cellular and ultrastructural levels.